Sheet pick-up and conveying device



July 19, 1966 A. SCHWEBEL.

SHEET PICK-UP AND CONVEYING DEVICE 5 Sheets-Sheet 1 Filed Aug. 27, 1964INVENTOR.

ADOLF SCf/WEBEL BY Haw MMQ/ July 19, 1966 A. SCHWEBEL SHEET PICK-UP ANDCONVEYING DEVICE Filed Aug. 27, 1964 5 Sheets-Sheet 2 INVENTOR. ADOLF'SCHWEEEL BY MGM/q, 0W4, W

July 19, 1966 A. SCHWEBEL 3,261,601

SHEET PICK-UP AND CONVEYING DEVICE Filed Aug. 27, 1964 3 Sheets-Sheet 5INVENTOR. ADOLF' SCHWEBEL BY HM United States Patent 3,261,601 SHEETPICK-UP AND CONVEYING DEVICE Adolf Schwebel, Offenbach (Main), Germany,assignor to Mabeg Maschinenbau G.m.b.H., Nachf. Hense 8; PleinesG.m.b.H. & Co., Offenbach (Main), Germany Filed Aug. 27, 1964, Ser. No.392,448 11 Claims. (Cl. 27111) The present invention relates to a sheetfeeding device for withdrawing successive sheets from a stack or pile ofsheets and conveying the withdrawn sheets in the form of a continuouslyflowing line of overlapping sheets, and more particularly, to a deviceof this kind in which the sheets are successively withdrawn bysequentially controlled blowing and suction means which move along anendless path in the direction of the sheet transport and a returndirection opposite thereto and which, when moving in the returndirection, slide under a lifted sheet and press such lifted sheetagainst transport means continuously rotating in the direction of thesheet transport.

With devices of this kind as heretofore known the top sheet of a stackis lifted at its forward edge by suction means and after having beentransported through a predetermined distance is transferred to the nextfollowing suction means which, in turn, transfers the sheet to othertransport means such as a conveyor table a roller, etc.

Such devices are limited to handling certain sizes and qualities ofsheets and have a comparatively low output.

It is an object of the invention to provide a novel and improvedsheet-feeding device which is capable of handling practically all sizesand qualities of sheets and which is simple and reliable in constructionand operation.

It is also an object of the invention to provide a novel and improvedsheet-feeding device of the general kind above referred to which canfeed sheets at very high rates of feedmodern printing presses use 30,000sheets per hour and more-and also at low rates of feed whereby a deviceaccording to the invention is useful not only for larger runs but alsofor small runs, pilot runs, rush jobs, etc.

A further object of the invention is to provide a novel and improvedsheet-feeding device of the general kind above referred to whichdelivers sheets accurately oriented so that they reach, the printingpress or another treatment station in the correct position.

The aforementioned object, features and advantages and other objects,features and advantages which will be pointed out hereinafter areattained by providing ahead of the forward edge of a stack or pile ofsheets, blowing nozzles for loosening up the sheets in the top layer ofthe stack and mounting each of the suction and blowing means lengthwisedisplaceable against spring action in a support. Each support in turn issuspended on suspension means and suitable drive means impart to thesuspension means, together with the support means and the suction andblowing means, a motion along a closed path, preferably a circular path.The motion of the suspension means is transmitted to the suction andblowing means by a spring superimposed between the support means andsaid means and is controlled by the engagement of the support means withstationary camming surfaces and by engagement of the suction and blowingmeans, preferably by means of rollers on the suction and blowing means,with rotary sheet transport means disposed posterior of the suctionmeans in the direction of the sheet travel. As a result, the path of thesuction and blowing means in respect to the top side of the stackdiverges partly from that imposed upon the suspension means and is soarranged that suction and blowing means are sequentially moved into andout of engagement with the top surface of the stack to withdrawsuccessive sheets therefrom.

A rotary sheet-deflecting means is preferably provided ad acent to theanterior part of the stack as seen in the direction of the sheettransport to direct successive lifted sheets between the top side of thesuction and blowing means and the transport means coacting therewith.

In the accompanying drawing several preferred embodiments of theinvention are shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational view of a sheet pick-up andconveying device according to the invention.

FIG. 2 is a fragmentary sectional view of a modification of the suctionand blowing assembly of the device.

FIGS. 3 through 6 show diagrammatically the parts of the suction andblowing assembly in different positions of operation.

FIG. 7 is a fragmentary sectional view of a further modification of thesuction and blowing assembly, and

FIG. 8 is a simplified elevational view of the device showing controlmeans therefor.

Referring now to the figures in detail, the suction and blowing assemblyof the sheet pick-up and conveying device comprises several suction andblow heads. Three heads 1, 2 and 3 are shown but it should be understoodthat a smaller or greater number of heads may be provided. In FIG. 1 twoheads and in FIG. 8 one head are shown for clarity of illustration. Eachhead is supported by and in communication with a pipe 4, 5 and 6respectively. The pipes should be visualized as being alternatelyconnected to a suitable supply of suction or pressure air as will bemore fully explained hereinafter and are supported by a supportstructure 7 for each pipe in which the pipes and with it the heads arelengthwise slidable. The pipes and hence the heads are springloaded bymeans of springs 10 as is shown for pipe 4.

Adjustable nuts 13 retain each pipe in a position such that the headsand, more specifically, the orifices 16 in the heads are at apredetermined distance in reference to the top sheet of a stack or pile17 when the heads are in the operational position for gripping andlifting the top sheet as will be more fully described hereinafter. Thesuitable spacing of the orifices 16 in reference to the top layer of thestack is a matter of practical experience and well understood. Thelifting and the control of stack 17 as it is being depleted do notconstitute part of the invention and are hence not described orillustrated in detail.

To permit adjustment of the angular position of each pipe in referenceto its support structure 7, a bracket 18 is provided for each pipe. Eachof the brackets mounts a set screw 21 which coacts with parts of therespective support frame to vary the angular position of the pipes andhence of the heads thereon by adjusting the set screws.

The support frames and the suction and blowing assemblies supportedthereon as previously described are suspended by suitable suspensionmeans shown as bolts 27 and 28 respectively and 30 and 31 respectively.The two sets of bolts rotate about axes 33a and are driven by drivesdiagrammatically indicated at 33 and 33b in a well understood manner.

As it is shown in FIG. 1, each support structure further includes amounting arm 24 and 25 respectively. Each mounting arm is directlylinked at one end to the main body of the support structure by the lowerbolts 27 and 28 respectively but coacts at the other end with the mainbody through an interposed loaded spring 34. Each spring presses therespective support structure and with it the respective suction andblowing assembly into coaction with a camming surface 40a of astationary cam member 40 by means of a cam follower 37 mounted in aprotrusion or nose extending from the respective support structure. Eachcam member 40 may be adjusted as to its effective height by a suitableconventional adjustment means indicated at 65.

As a result of the coaction between the rollers and the camming surfacesthe heads are sequentially moved into the gripping position with the topsheet of stack 17 While the support structures perform a pivotalmovement about the respecive suspension bolts 27 and 28 respectively.Head 1 and the associated structural elements which are shown in heavyfull lines, are illustrated in the positions in which the head ispicking up the uppermost sheet.

As it is evident from the previous description, the paths impressed uponthe mounting arms 24 and 25 are distorted due to the action of springs34 and the movement of rollers 37 along the c-amming surfaces 40a. Thepaths followed by the heads during the completion of the circular pathsby bolts 27 and 28 are indicated by a dash-dotted outline 66. When theheads follow the outline 66 they are sequentially moved downwardly intothe gripping position with the uppermost sheet on stack 17. Afterleaving circular portion 41 of outline 66 they are pressed back againstthe action of springs 10 while travelling along portion 42 of outline66. Finally, while travelling along portion 43 they move into engagmentwith a sheet transport roller 44.

Turning now to FIGS. 3 to 6, sheet II which should be visualized ashaving been lifted by the head sequentially preceding the head noweffecting lifting of the uppermost sheet, is pulled along the top sideof the head now in its top position (head 3) by the coaction of thishead with a roller 44. To facilitate transport of the sheets betweenroller 44 and the respective head, a pressure roller 46, 47 and 48respectively protrudes from the top side of each head. As it isindicated in FIG. 2 for roller 46, each roller may be supported by aschematically indicated leaf spring 67 which engages a pin 67a slidablein a slot 46a of the roller.

To facilitate guidance of lifted sheets into the positions betweenroller 44 and the respective counter roller 46, 47 and 48, a rotarydeflecting roller 49 is preferably provided. As it is shown in FIG. 8,this roller is in engagement with a roller 49a which in turn engagesroller 44. Rollers 49 and 49a may be adjustably mounted. There is showna pivotal support bracket 70, the angular position of which may bevaried by .a set screw 70a coacting with an abut member 80 against whichit is pressed by a spring 81.

When and while the heads move along the path 66, pipes 4, and 6 arefirst connected to a source of suction and then to a source of pressureair. The control of the supplies of suction and pressure air may beeffected by suitable control means. Such control means arediagrammatically shown in FIG. 8 as comprising a Maltses cross or Genevamechanism, including a Maltese cross 73 within which rotates a controlsleeve 72. This sleeve has in its outer wall a circumferential channel74 which, through ports 75, communicates with appropriate slots 73a ofthe Maltese cross and through a duct 76 with a pipe 77 connectable to asource of pressure air or a suction source by a suitable changoverconnector. Slots 73a are sequentially engaged with the ends of pipes 4,5 and 6 as it is indicated by arrows. The Maltese cross is stepwisedriven by a drive mechanism broadly indicated at 78. Suitable cyclingmeans of the kind herein referred to are conventional and do notconstitute part of the invention. Accordingly, they are not described orillustrated in detail.

When the head :1 is in the position shown in FIG. 3, that is in aposition in which it has just gripped and lifted the forward edge ofasheet I, suction is made effective in head 1. The sheet I is now movedinto the position shown in FIG. 4 whereupon pressure air is supplied tothe head. As a result the head will release the gripped sheet which willdrop upon the top side of the sequentially following head 2 which in themeantime has moved into a position above the stack and underneathhead 1. At the same time the third head 3 has transferred a sheet III tothe top side of the head 1 and this sheet is now forwarded to thetransport roller 44, the movement of the head being controlled byportion 43 of the path 66, which conveys the sheet to the feed table 50as part of a. web 45 formed by the overlapping sheets.

To assist in the picking-up and conveying of sheets, an air pipe 51 isprovided to which pressure air is suitably supplied and which is dividedinto two branches 52 and 53. Branch 53 directs a flow of air indicatedby an arrow 54 against the sheets in the top portion of stack 17 toloosen up the stack at its side facing the suction and blowing assembly.The second branch 53 directs an air flow 55 against the bottom side of alifted sheet to facilitate separation of the sheet from the top side ofthe respective head. A third air flow 56 may be provided to facilitatefurther the separation of the lifted sheets from the top sides of theheads by directing the air flow toward deflection roller 49.

The rotary deflection roller 49 which is disposed above the suction andblowing assembly engages and bends each lifted sheet so that the sameobtains a certain stiffness of its entire length which prevents thelifted forward part of each sheet to drop back into its initialposition.

Each of the heads 1, 2 and 3 is provided with a safety valve to protectagainst a failure of the suction. As it is shown in FIG. 1 for head 1,the safety valve comprises a valve ball 57 which is urged by a spring 58away from its seat 59. A vent 60 communicates through a duct 61 withpipe 4 and can also communicate with a bore 61 issuing in the top sideof the head.

When a sheet is sucked on by the orifices 16 of head 1, the prevailingsuction within duct 61 Will increase and as a result valve ball 57 willbe pressed against seat 59 against the action of spring 58, thuspreventing the ingress of air through the bore 62 toward the suctionorifices 16 of the suction head which would jeopardize the retention ofthe gripped sheet.

As a result the gripped sheet is safely carried within reach of thesequentially next head to be acted upon by the same. Due to theprovision of duct 60 a subatmospheric pressure is obtained in bore 62which causes the previously lifted and conveyed sheet to be sucked on.The resulting covering of the top side 63 of the head by the sucked-onsheet causes a reduction of the suction within the valve chamber 71 suchthat spring 58 can now.

lift ball 57. away from its seat.

The safety device as shown in FIG. 7 is particularly suitable when thesheet-feeding device with which the pickup and conveying device coactsis operated comparatively slowly and also when the installation is newlyset up for operation, or a pilot run is made. Without the safety devicea sheet sucked on by the suction heads may not be sufficiently held bythe same, or it may fall off when and while being transported by therollers 46, 47 and 48 respectively and transport roller 44.

While the invention has been described in detail with respect to certainnow preferred examples and embodiments of the invention, it will beunderstood by those skilled in the art after understanding theinvention, that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, and it is intendedtherefore to cover all such changes and modifications in the appendedclaims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A device for withdrawing successive sheets from a stack of sheets andconveying said sheets in the form of a continuously flowing line ofsheets, said device comprising conduit means for directing a flow ofpressure air against one side of the stack to loosen up the sheets inthe upper portion of the stack, several suction and blow ing means eachincluding a head and a pipe secured to the head and disposed adjacent tosaid side of the stack, a support means for each of said suction andblowing means, each of said support means including a support membersupporting one of the pipes, lengthwise displaceable in reference to thesupport member, a first yieldable means urging the suction and blowingmeans into a predetermined position of displacement, a pair ofsuspension members for each of said support means to suspend the same,one of the suspension members of each pair being pivotally linked to therespective support member, a second yieldable means interposed betweenthe other suspension member of each pair and the respective supportmember, drive means coacting with the suspension members of each pairfor sequentially moving the suspension members together with therespective support member and the suction and blowing means along aclosed path,

a stationarily mounted cam member for each support member, each of saidsecond yieldable means urging the respective support member intoengagement with the respective camming member during part of said closedpath, and rotary sheet transport means disposed above each of saidheads, said transport means being engageable with the top sides of therespective heads to displace the suction and blowing means against theaction of said first yieldable means for part of the movements imposedto the same by the movements of said suspension members whereby theheads travel in a closed path diverging from that of the suspensionmembers and causing the heads sequentially to lift one sheet and topress a sheet lifted by an adjacent head against said transport means.

2. A device according to claim 1 wherein each of said support membersmounts a roller engaging the respective camming member.

3. A device according to claim 1 and further comprising rotarydeflecting means for directing a lifted sheet into a position betweenthe respective transport means and the respective head.

4. A device according to claim 3 and comprising means for adjusting theposition of the deflecting means in .refer ence to said heads.

5. A device according to claim 1 wherein a roller protrudes from the topside of each head for coaction with the respective transport means.

6. A device according to claim 5 wherein each of said rollers isyieldably mounted in the respective head.

7. A device according to claim 1 wherein said camming member isadjustable as to its height in reference to the respective supportmember coacting therewith.

8. A device according to claim 1 and comprising adjustment means foradjusting the angular position of each suction and blowing means inreference to the respective support means.

9. A device according to claim 1 wherein said pressure air conduit meansincludes an orifice for directing flows of pressure air from beneathupon a lifted sheet to assist in pressing the same against the transportmeans by the respective head.

10. A device according to claim 1 and further comprising rotarydeflecting means for directing a lifted sheet between the respectivetransport means and the respective head, said pressure air conduit meansincluding a branch conduit for directing a flow of air toward saiddeflecting means.

11. A device according to claim 1 wherein each of said heads includes aduct communicating with the respective pipe and issuing in the top sideof the respective head, and wherein a valve is provided in each of saidducts, said valves being spring-biased into the open position and heldin the closed position against the spring action by suction in therespective duct, reduction of said suction by closing of the duct due toa sheet covering the top side of the respective head releasing the valvefor opening by spring action.

References Cited by the Examiner UNITED STATES PATENTS 1/1958 Williams27126 1/1959 Backhouse 27126

1. A DEVICE FOR WITHDRAWING SUCCESSIVE SHEETS FROM A STACK OF SHEETS ANDCONVEYING SAID SHEETS IN THE FORM OF A CONTINUOUSLY FLOWING LINE OFSHEETS, SAID DEVICE COMPRISING CONDUIT MEANS FOR DIRECTING A FLOW OFPRESSURE AIR AGAINST ONE SIDE OF THE STACK TO LOOSEN UP THE SHEETS INTHE UPPER PORTION OF THE STACK, SEVERAL SUCTION AND BLOWING MEANS EACHINCLUDING A HEAD AND A PIPE SECURED TO THE HEAD AND DISPOSED ADJACENT TOSAID SIDE OF THE STACK, A SUPPORT MEANS FOR EACH OF SAID SUCTION ANDBLOWING MEANS, EACH OF SAID SUPPORT MEANS INCLUDING A SUPPORT MEMBERSUPPORTING ONE OF THE PIPES, LENGTHWISE DISPLACEABLE IN REFERENCE TO THESUPPORT MEMBER, A FIRST YIELDABLE MEANS URGING THE SUCTION AND BLOWINGMEANS INTO A PREDETERMINED POSITION OF DISPLACEMENT, A PAIR OFSUSPENSION MEMBERS FOR EACH OF SAID SUPPORT MEANS TO SUSPEND THE SAME,ONE OF THE SUSPENSION MEMBERS OF EACH PAIR BEING PIVOTALLY LINKED TO THERESPECTIVE SUPPORT MEMBER, A SECOND YIELDABLE MEANS INTERPOSED BETWEENTHE OTHER SUSPENSION MEMBER OF EACH PAIR AND THE RESPECTIVE SUPPORTMEMBER, DRIVE MEANS COACTING WITH THE SUSPENSION MEMBERS OF EACH PAIRFOR SEQUENTALLY MOVING THE SUSPENSION MEMBERS TOGETHER WITH THERESPECTIVE SUPPORT MEMBER AND THE SUCTION AND BLOWING MEANS ALONG ACLOSED PATH, A STATIONARILY MOUNTED CAM MEMBER FOR EACH SUPPORT MEMBER,EACH OF SAID SECOND YIELDABLE MEANS URGING THE RESPECTIVE SUPPORT MEMBERINTO ENGAGEMENT WITH THE RESPECTIVE CAMMING MEMBER DURING PART OF SAIDCLOSED PATH, AND ROTARY SHEET TRANSPORT MEANS DISPOSED ABOVE EACH OFSAID HEADS, SAID TRANSPORT MEANS BEING ENGAGEABLE WITH THE TOP SIDES OFTHE RESPECTIVE HEADS TO DISPLACE THE SUCTION AND BLOWING MEANS AGAINSTTHE ACTION OF SAID FIRST YIELDABLE MEANS FOR PART OF THE MOVEMENTSIMPOSED TO THE SAME BY THE MOVEMENTS OF SAID SUSPENSION MEMBERS WHEREBYTHE HEADS TRAVEL IN A CLOSED PATH DIVERGING FROM THAT OF THE SUSPENSIONMEMBERS AND CAUSING THE HEADS SEQUENTIALLY TO LIFT ONE SHEET AND TOPRESS A SHEET LIFTED BY AN ADJACENT HEAD AGAINST SAID TRANSPORT MEANS.